Q. Can AutoPIPE model have multiple piping systems (gas and fluid) not connected in the same model?


Question:

Is it possible to model different type of piping systems (gas and fluid) that are not connected to each other?

Can AutoPIPE have two separate pipelines in one model?

Answer: 

When modeling more than one group of connected segments in AutoPIPE, the training documentation refers to these as disconnected segments. To verify whether a model contains disconnected systems, use AutoPIPE’s Connected Segments command (Select > Segments > Connected Segments), imaged below. 

In larger models with complex piping layouts, this tool is especially useful for identifying which pipeline segments are connected to one another. It can also be used to isolate or hide a group of segments while working on a different portion of the model.

To answer the question, can AutoPIPE model disconnected systems, where a group of connected segments represents a different type of piping system, ex. Fluid or Gas?

Yes, it is possible to model multiple piping systems (groups) in AutoPIPE so long as the total number of segments in the model remains under the segment numbering limitation (March 2026: Alphanumeric A-Z and AA-ZZ).

Example modeling approach:

    1. Insert one or more PipeIDs for System A (for example, a GAS system). For each PipeID, carefully enter all required properties, including pipe size, specific gravity, material properties, and any other relevant parameters. Verify that these properties are correct for this piping system where the PIPEid is to be used.
    2. Insert a new segment starting point and start modeling complete piping system (such as a Gas system), using the PIPEids defined for this system, continue adding pipe segments to define the piping layout and supports as required.
    3. Suggest to select Segment tab on the input grids and enter Line Number data to help keep the segments organize. One does not need to enter just a line number but can use this field to enter useful information about the segment or group of segments. Note, when double selecting the column heading in the grids the entire column is placed in alphabetical order progressing, double click again reverse the order, etc.. 
    4. Next, insert one or more PipeIDs for System B (for example, a Fluid system). For each PipeID, carefully enter all required properties, including pipe size, specific gravity, material properties, and any other relevant parameters. Verify that these properties are correct for this piping system where the PIPEid is to be used.
    5. Insert a new segment starting point and start modeling complete piping system (such as a Fluid system) using the PIPEids defined for this system, continue adding pipe segments to define the piping layout and supports as required.
    6. Again, suggest to select Segment tab on the input grids and enter Line Number data to help keep the segments organize. One does not need to enter just a line number but can use this field to enter useful information about the segment or group of segments. Note, when double selecting the column heading in the grids the entire column is placed in alphabetical order progressing, double click again reverse the order, etc.. 
    7. Repeat process above for each disconnected system (ex. Gas, Fluid 1, Fluid 2, etc..) to be added into a single model file. 

    8. When modeling support frame structures, each disconnected piping system (for example, Gas 1, Gas 2, Fluid 1, etc.) may have their its own independent beam structure. Or, two or more disconnected piping systems can share the same beam structure (see AutoPIPE Help for details).


      • For example, the image above may represent one or more disconnected piping systems supported by a common frame structure. In this example, the piping with the vertical elbow could represent a GAS 1 system, while the piping with the horizontal elbow could represent a Fluid 1 system.
    9. Specify all data on Press/Temp/PipeID tab of the input grids for each of the Pressure/Temperature case set for the model. Hint, use color plots to verify pressure and temperature distribution across the model. 
    10. While being mindful of the piping systems, apply all loadings as needed (Wind, Static Seismic, water, wave, etc..)
    11. Add all Analysis sets needed per project specification. Bentley technical support cannot dictate how many analysis set are needed for your project. Again, this should be established by project documentation. 
    12. Suggest before running an analysis, perform a thorough review of the model input to confirm all the settings are correct. AutoPIPE's color maps are very useful during this step.
    13. Review results.

Note:

Modeling multiple piping systems within a single model offers several advantages, including a reduced number of models to maintain and improved visualization for clash detection. However, there are also drawbacks. The overall modeling effort becomes more complex, greater care is required to ensure each system is modeled correctly, and dynamic analysis will include the combined mass of all the disconnected systems during modal analysis. As a result, the calculated frequencies and mode shapes during modal analysis may differ from those obtained if each piping system were modeled separately in their own independent model files.